If you understand that the Republicans are a huge problem in California while they have the veto power over the budget because of a 2/3 requirement, you choose between voting for the people who are supporting good policies, the Democrats, or the one who are supporting bad policies, the Republicans, and a vote for Whitman is for more problems, starting with her turning California into the only state in the country taxing workers, but not the rich on their passive income, greatly expanding our debt to put more money in the pockets of the rich.
Similarly for the country, you pick the party passing the good policies, the Democrats, or the party blocking them by abusing the filibuster and wanting bad policies.